Am I (F21) in the wrong for telling my sister (F18) not to come over because her period will ruin my sheets?

I told my sister she can't spend the night with me because I just got an expensive set of sheets and I don't want her period to ruin them. She is currently on her period and I just got the new sheets last week. She got mad and said that I shouldn't let that get in the way of family, but I'm not willing to ruin my sheets. Am I in the wrong?<br><br>Additional info: My sister has very heavy periods (she goes through 8-10 tampons/pads per day)